1. Technical Field
The present disclosure relates to light guides and, particularly, to a light guide and an illumination device using the light guide.
2. Description of Related Art
Light guides which are a quarter of a cylinder in shape are used in illumination devices to allow the illumination devices to be compactly installed into an intersectional corner between two orthogonal surfaces, e.g., a corner between a sidewall and a ceiling. Such a light guide typically includes two orthogonal planar surfaces and a cylindrical surface connecting the planar surfaces. In use, a light source is placed in front of one of the planar surfaces (referred to as the incident surface) and illuminates the light guide, which directs light rays to emit out from the cylindrical surface (referred to as the emitting surface). One of the challenges of utilizing such a light guide in an illumination device is: light rays entering the light guide at a point far away from the planar surface without the light source (referred to as the connecting surface) may experience total internal reflection on the emitting surface and are either gathered to emit out from a zone of the emitting surface near the connecting surface or absorbed by the connecting surface, decreasing light uniformity of the emitting surface and light usage efficiency of the illumination device.
Therefore, it is desirable to provide a light guide and an illumination device having the same, which can overcome the above-mentioned problems.